With the prevalence of computers, clients basically all need to install anti-virus software to scan files in a computer. When the anti-virus software is scanning, a lot of CPU operations and disk operations are needed, which makes the scanning process long and affects the system speed. However, for files in computers, many are identical, for example, files of Windows, installation packet files, help files, and compressed files, etc. of much softwares.
In the prior art, when scanning the first time, anti-virus software of a client will comprehensively scan all the files within a computer, and will scan various content in a file. For a file comprising large content, it consumes quite much time for scanning, this will lead to a very long time for the first scanning. For example, for a compressed packet, the prior art will, according to a normal scanning process, decompress the content in the compressed packet and scan one by one to ensure that the files are secure. Therefore, for a compressed packet, the scanning time of the prior art is relatively long, and hence the time for the whole scanning is prolonged, whereas for a user, the CPU operations and disk operations being occupied for a long time due to a long-time scanning affect the system speed, thereby influencing the use of the computer by the user.
In addition, anti-virus software will generally record secure files last scanned into a white list, and then when scanning the next time, match a current file with files in the white list one by one; if they match, then skip the current file and enter into a next file scanning process; if they do not match, then fully scan the entire content of the unmatched file, and enter into a next file scanning process after the scanning is finished. In this process, it is needed that the matching and scanning process can be performed on a next file only after a previous file is matched or fully scanned, and the wait time for the next file is relatively long, which gives rise to the problem of the time for scanning the files of the whole system by the whole anti-virus software being relatively long.